1. Field of the Invention
The present invention relates to a keyboard musical instrument.
Priority is claimed on Japanese Patent Application No. 2013-187382, filed on Sep. 10, 2013, the content of which is incorporated herein by reference.
2. Description of Related Art
Typically, keyboard musical instruments including acoustic pianos such as grand pianos and upright pianos and electronic pianos include a fall board that covers a keyboard (for example, refer to Japanese Examined Utility Model Application, Second Publication No. H03-39825). In the related art, in an acoustic piano or an electronic piano having an appearance and design similar to that of an acoustic piano, a fall board is made of wood and has a predetermined thickness.
However, when the fall board is made of wood and has a predetermined thickness, the weight of the fall board is heavy, which causes a problem in that the fall board is not easily opened and closed.
The fall board disclosed in Japanese Examined Utility Model Application, Second Publication No. H03-39825 is made of a resin material. However, even if a fall board for an acoustic piano (or an electronic piano having a similar appearance and design) is made of a resin material, the weight of the fall board is still heavy. A configuration in which the thickness of a fall board of the above-described acoustic piano or the like is reduced to reduce the weight of the fall board can also be considered. In this case, however, the appearance and design of the acoustic piano or the like is poor.
In addition, in the related art, in order to allow a fall board of the acoustic piano or the like to be easily opened and closed, a configuration in which a damper structure is provided to the fall board is also disclosed. However, since the damper structure is exposed to the outside, the appearance and design of the acoustic piano or the like is poor. Further, since the damper structure is expensive, the manufacturing cost of the acoustic piano or the like increases.